The Fundamentals of Land-Based Missile Defense
 

Land-based missile defense works by detecting the launch of ballistic missiles, tracking their ascent through the sky to determine their trajectory, launching another missile from within the United States to intercept the trajectory of the incoming missile, and colliding with the descending warhead in it's late midcourse or terminal phase- the time period after the warhead has separated from the missile begining its descent from space back to the Earth and before the warhead reaches it's detonation altitude.

In order to accomplish the first step of the land based intercept process- launch detection- the United States relies on the aging satellite system known as the Defense Support Program. Early detection and tracking is an essential component of all missile defense system architectures and for this reason all system architectures will benefit from the delployment of the SBIRS satellite system derived from the Brilliant Eyes program that will use more modern technology in target aquisition in tracking. The much talked about X-Band Radar will also assist in the tracking function but is more specifically designed for the demanding task of late mid-course and terminal phase target aquisition.

After detection and initial tracking, the United States defense forces must then decide whether or not to engage the incomming missile. This is a critical and often overlooked step shared by all system architectures as well. A part of Battle Management/Command, Control, Communcications, Computers and Intelligence [BMC4I]  component, the decision to engage must be made quickly as often the speed of ballistic missiles leaves only a  narrow window in which to launch an interceptor.